1. Field of the Invention
The present invention relates to a pipe type solid insulation cable system, a method of constructing the pipe type solid insulation cable system and a method of cooling the pipe type solid insulation cable system.
2. Description of the Related Art
Conventionally, a pipe type oil filled cable (or a high pressure fluid filled (HPFF) pipe type cable, hereinafter, simply referred to as an “OF cable”) system is known as an underground bulk power transmission line. The OF cable system is configured to include an OF cable, which is inserted in a steel pipe for OF cable, and high pressure insulating oil is filled in the steel pipe for OF cable to be circulated. With this configuration, insulating properties of the OF cable can be improved and the OF cable can be cooled as well.
However, as high pressure is applied to the insulating oil in the steel pipe for OF cable in the OF cable system, there is a possibility that the insulating oil leaks from joint portions of the steel pipes for OF cable. Thus, there is a risk that peripheral environment is affected by the leakage of the insulating oil.
Thus, recently, the OF cable of the OF cable system has been substituted by a solid insulation cable (a cross-linked polyethylene insulated polyvinylchloride sheathed cable or an XLPE cable, simply referred to as an “XLPE cable”) (Patent Document 1, for example).